Japanese Oscar-winning animator Hayao Miyazaki said Friday he was retiring from feature-length movies because he could no longer maintain the pace -- but would still go into work every day apart from Saturday.

The acclaimed 72-year-old director said he had become too old for the kind of craftmanship and physical work required for major commercial projects.

"In the past, I have said many times I would quit. This time, it's for real," Miyazaki told a Tokyo press conference, packed with some 600 reporters, including 70 television camera crews, from around the world.

"Now, I am free. Free to do things, free not to do things," he said.

Miyazaki has won hearts and accolades around the world in a career that began in the 1960s, blazing a trail for the genre of Japanese cartoons known as "anime".

He will leave behind a legacy of commercial and artistic successes unmatched by contemporaries.

His most famous works internationally have been "Princess Mononoke" and "Spirited Away", which helped him make the transition from an already widely acclaimed career in Japan to a far broader audience.

"Spirited Away" won an Oscar for best animated feature, the first Japanese film to do so, and scooped the Golden Bear prize at the Berlin International Film Festival, among other major gongs.

He began his career in 1963 as a staff animator. His first feature-length film was "The Castle of Cagliostro" (1979), featuring the grandson of fictional master thief.

He gained critical acclaim and cult following for "Nausicaa of the Valley of the Wind" (1984) and co-founded Studio Ghibli, which has become Japan's premier animation studio.

His latest work, "The Wind Rises" has been seen by nearly 7.5 million people and has so far grossed 9.23 billion yen ($92.7 million) in its first seven weeks.

Despite his latest retirement pronouncement, Miyazaki said he will continue to commute to the studio with a lunch box prepared by his wife, but will try to take break on Saturdays.

A heavy smoker, Miyazaki said he has "various" health problems, but declined to discuss details.

Looking back at his career, he said making films was a continuous struggle filled with agony.

He said he had always asked himself whether his movies are worth making -- or whether he can finish his projects at all.

He has also become slower in drawing storyboard, and said he cannot labour through physical tasks like he did as a young professional, Miyazaki said.

"I want to work for another 10 years. But I cannot keep working in the same way."